JP3972607B2 - Vehicle position detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle position detection device that detects the position of a vehicle using a beacon, and more particularly to an improvement for improving the position detection accuracy of the vehicle.
[0002]
[Prior art]
Conventionally, as a method for detecting the traveling position of a vehicle for cargo handling / transportation in a premises such as a factory, as described in, for example, Japanese Patent Publication No. 7-20839, a floor of a traveling path of a vehicle 2. Description of the Related Art It is known that a magnetic tape is installed on a surface, and the magnetism is detected on the vehicle side so as to grasp the traveling position of the vehicle relatively accurately.
[0003]
On the other hand, as a position detection method used for an automobile navigation system on a general road or the like, for example, as described in Japanese Patent No. 2505934, a radio wave beacon transmitter is installed at a key point of the road, and from there It is known that a vehicle (receiving position information) transmitted at a constant time interval is received on the vehicle side so as to grasp the traveling position of the vehicle more accurately.
[0004]
[Problems to be solved by the invention]
In the former detection method (method using magnetic tape) described above, when the vehicle travels along a fixed track, the magnetic tape can be installed on the track, so that relatively high position detection accuracy can be obtained. . However, when the vehicle travels without a track, there is a problem that it is difficult to cover the wide range with a magnetic tape because the width of the travel path is set to be considerably wide.
[0005]
On the other hand, in the latter detection method (method using a radio beacon) described above, a relatively wide reception area on the travel path of the vehicle (a reception area is a signal transmitted from a beacon transmitter can be received by a beacon receiver). Area), which can cover most of the travel path width even when the vehicle travels without a track. However, in radio wave beacons, the edge (boundary line, outline) of the reception area cannot be sharply formed due to the nature of the radio wave transmitted from there and the directivity of the antenna. At most, it was only about 1 m, and it was difficult to achieve higher accuracy.
[0006]
An object of the present invention is to provide a vehicle position detection device that can sufficiently cover the range of the travel path width of a vehicle and that can greatly improve position detection accuracy in view of the above-described conventional problems. .
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is configured as follows.
That is, the present invention is an optical beacon transmitter that is installed at a key point of a traveling path of a vehicle and repeatedly transmits a signal including its own position information at a constant period, and is transmitted from the optical beacon transmitter mounted on the vehicle. The present invention is applied to a vehicle position detection device that detects a traveling position of a vehicle based on information received by the optical beacon receiver, and has the following characteristics. Have.
[0008]
First And a counting means for counting the number of times the signal is received by the optical beacon receiver when the vehicle passes through the reception area of the signal transmitted from the optical beacon transmitter, and the reception counted by the counting means. Detailed information acquisition means for acquiring detailed information related to the travel position of the vehicle based on the number of times ing .
[0009]
Here, the detailed information related to the travel position of the vehicle is more detailed information that can assist the vehicle position detection, and is various information that can further improve the position detection accuracy. A more accurate position in the traveling direction of the vehicle, a position in the vehicle width direction of the vehicle, a traveling direction of the vehicle (which direction is traveling on the traveling path), and the like. The detailed information acquisition unit may acquire only one of these pieces of information, or may acquire a plurality of pieces of information.
[0010]
Since the optical beacon transmitter can form a relatively wide reception area on the travel path of the vehicle, it can cover most of the travel path width. Moreover, unlike the radio beacon transmitter, it is possible to make the edge of the reception area extremely sharp.
[0011]
In addition, since a signal including its own position information (ID information indicating the installation position of the optical beacon transmitter itself) is repeatedly transmitted from the optical beacon transmitter at a constant period, in the present invention, the counting means is as described above. And the detailed information acquisition means, the above-mentioned “detailed information” can be acquired based on the number of signal receptions by the optical beacon receiver when the vehicle passes through the reception area.
[0012]
That is, when the signal is transmitted at a constant time period and the vehicle passes through the reception area at a stretch, the speed at the time of passing can be regarded as almost constant, so the number of signal receptions counted at the time of passing is This corresponds to the length in the vehicle traveling direction at the location where the vehicle passes in the reception area. That is, the longer the reception area is in the vehicle traveling direction, the greater the number of signal receptions. Conversely, the shorter the reception area is in the vehicle traveling direction, the fewer the number of signal receptions. Therefore, coupled with the sharpness of the edge of the reception area, calculating a more accurate position in the vehicle traveling direction based on the number of signal receptions, or by appropriately devising the shape of the reception area as follows, It is also possible to know the position of the vehicle in the vehicle width direction and the traveling direction of the vehicle.
[0013]
As an example, In the invention according to claim 1, the vehicle is assumed to travel at a constant speed, The reception area is set so that the length in the vehicle traveling direction differs at the position in the vehicle width direction (for example, in a trapezoid shape). In this way, since the number of signal receptions differs depending on which position in the vehicle width direction in the reception area the vehicle has passed, it is possible to acquire the position of the vehicle in the vehicle width direction based on the number of receptions. is there.
[0014]
As another example, In invention of Claim 2, The reception area is divided into a plurality of (for example, two) regions in the vehicle traveling direction, and the lengths of the plurality of regions in the vehicle traveling direction are set to be different from each other. In this way, since the vehicle sequentially passes through the plurality of regions, for example, when the vehicle is divided into two regions, the vehicle moves from the longer region to the shorter region in the vehicle traveling direction. If the vehicle has traveled, the number of receptions counted in the longer region is greater than the number of receptions counted in the shorter region. Vehicle traveling direction) can be acquired.
[0015]
As another example, In invention of Claim 3, Combining the above two examples ing . That is, Suppose the vehicle is traveling at a constant speed, The reception area is divided into a plurality of regions in the vehicle traveling direction, the lengths of the plurality of regions in the vehicle traveling direction are different from each other, and the length of the vehicle traveling direction in each of the plurality of regions is the vehicle. Set differently in the position in the width direction. In this way, it is possible to acquire both the traveling direction of the vehicle and the position in the vehicle width direction.
[0016]
Of course, by counting the number of signal receptions, it is possible to acquire not only the position in the vehicle width direction and the traveling direction of the vehicle, but also a more accurate position in the vehicle traveling direction.
Note that the signal transmission cycle by the optical beacon transmitter is preferably set based on the vehicle speed and the required position detection accuracy. For example, it is conceivable to set a value (for example, about one half) smaller than the value obtained by dividing the required position detection accuracy by the vehicle speed as the transmission cycle. Here, the value smaller than the division value is due to the delay of the processing timing of the received signal.
[0017]
As described above, the present invention not only enables position detection that sufficiently covers the range of the travel path width of the vehicle by the extremely sharp reception area of the edge, but also provides detailed information related to the travel position of the vehicle. By making it possible to acquire the position detection accuracy can be greatly improved.
[0018]
Although the present invention is applied to a vehicle position detection device using an optical beacon, the vehicle that is the position detection target may be a cargo handling / transportation vehicle used on the premises. It may be a normal car traveling on a general road. Such a vehicle position detection device can be used in a system for managing the operation route of a manned vehicle, an automatic driving (automatic driving) system of an unmanned vehicle, or the like when a detection target is a private vehicle. Further, when the detection target is a general vehicle, it can be used in an automobile navigation system or the like on a road traffic network.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<First embodiment of the present invention>
FIG. 1 is a diagram for explaining a vehicle position detection apparatus according to a first embodiment of the present invention, in which FIGS. 1 (a) and (b) are side views of a vehicle travel path in which an optical beacon transmitter is installed; It is a top view. In addition, this embodiment is an example applied to the apparatus which detects the traveling position of the vehicle for cargo handling and conveyance which drive | works a premise.
[0020]
As shown in FIG. 1, an optical beacon transmitter 3 is installed at a main point (for example, every 100 m) along the traveling path 2 of the vehicle 1. The installation location may be a high place (for example, a ceiling, a beam, or the like) in a factory, a warehouse, or the like, or may be a column or the like standing on the side of the traveling passage 2.
[0021]
On the other hand, the vehicle 1 is equipped with an optical beacon receiver 4 that receives the optical signal L transmitted from the optical beacon transmitter 3. The mounting location is preferably a location where the optical signal L can be efficiently received, such as the front upper portion of the vehicle 1.
The optical beacon transmitter 3 repeatedly irradiates the traveling path 2 with a planar light signal (for example, infrared light or visible light signal) L including its own position information (ID information) at a constant cycle, A reception area A having a predetermined shape is formed on the travel path 2 as shown in FIG. When the vehicle 1 passes through the reception area A, the optical beacon receiver 4 receives the optical signal L from the optical beacon transmitter 3. The reception area A formed by the optical beacon transmitter 3 can sufficiently cover the range of the travel path width of the vehicle, and the edge thereof is formed extremely sharply compared to that by the radio beacon. Can do.
[0022]
Here, the optical beacon transmitter 3 will be described in more detail with reference to FIGS. 2 and 3. 2 is a diagram illustrating a schematic configuration of the optical beacon transmitter 3, and FIG. 3 is a diagram illustrating a circuit portion of the optical beacon transmitter 3.
As shown in FIG. 2A, the optical beacon transmitter 3 includes a plurality of LEDs (light emitting diodes) 12 for irradiating the optical signal L outward in a light-shielded case 11. The plurality of LEDs 12 are mounted on the substrate 13 in an appropriately arranged state.
[0023]
The circuit portion mounted on the substrate 13 will be described in more detail. As shown in FIG. 3, a plurality of sets (for example, 8 sets) of circuits in which the LED 12 and the current limiting resistor 14 are connected in series are connected in parallel. These are connected between the switching element 16 that is driven on / off by the transmission signal output from the transmitter IC 15 and the DC power source 17, so that the optical signal L is transmitted from the plurality of LEDs 12 to the transmission signal. According to the output. Here, for example, as shown in FIG. 4A, the optical signal L includes a header portion L1 for synchronizing signals, a data portion L2 including ID information of the optical beacon transmitter 3, and the subsequent signal. The data is composed of a data sequence in which a series of codes composed of an idling portion L3 and so on for a certain period is defined as one cycle, and the code for one cycle is repeatedly output at a constant cycle. Note that the waveform of the optical signal L is substantially the same waveform as the transmission signal output from the transmitter IC 15, and the carrier is digital data (ID information or the like) as shown in FIGS. ) Is a signal obtained by amplitude modulation according to
[0024]
By using a plurality of LEDs 12 connected in parallel as a light source in this way, the light quantity of the optical signal L is increased, and as a result, the reception area A can be secured sufficiently wide with its edges kept sharp. Become. Although not shown in FIG. 2A, the current limiting resistor 14, the transmitter IC 15, the switching element 16, and the like are also mounted on the substrate 13.
[0025]
The case 11 is provided with a horn 18 on the irradiation end side of the optical signal L from the LED 12 for emitting the optical signal L in a predetermined direction while narrowing the region. Both the inside of the case 11 and the inside of the horn 18 are painted black, thereby preventing irregular reflection of the optical signal L inside the case 11 and the horn 18 and further sharpening the edge of the reception area A. I am trying. In addition, an aluminum block having holes individually drilled corresponding to the positions of the respective LEDs 12 is mounted on the substrate 13, and the plurality of LEDs 12 are respectively inserted and arranged in the individual holes. By aligning the optical axes, the edge of the reception area A can be further sharpened.
[0026]
A light shielding plate 19 for restricting the cross-sectional shape of the planar optical signal L to a predetermined shape is provided at the emission end of the horn 18. As shown in FIG. 2B, the light shielding plate 19 has a configuration in which a transparent window 19b having a predetermined shape capable of transmitting the optical signal L is disposed in a light shielding portion 19a capable of interrupting the optical signal L. The shape of the transparent window 19b is set based on the shape required for the reception area A, and the reception area A is formed in a shape substantially similar to the transparent window 19b. When various light shielding plates 19 having transparent windows 19b having different shapes are prepared and the shape of the reception area A is to be changed, the light shielding plate 19 having the transparent window 19b having a shape corresponding to the shape is attached. It is also possible to do so. Further, when the shape of the reception area A is used in a fixed manner, the light shielding plate 19 can be omitted by forming the shape of the emission end of the horn 18 equal to the shape of the reception area A.
[0027]
Subsequently, the optical beacon receiver 4 will be described in more detail with reference to FIGS. 5 and 6. 5 is a diagram showing a schematic configuration of the optical beacon receiver 4, and FIG. 6 is a diagram showing a circuit portion of the optical beacon receiver 4. As shown in FIG.
As shown in FIG. 5, the optical beacon receiver 4 includes a photodiode 22 capable of receiving an optical signal L in a light-shielded case 21, and the photodiode 22 is mounted on a substrate 23. .
[0028]
The circuit portion mounted on the substrate 23 will be described in more detail. As shown in FIG. 6, an electrical signal obtained by receiving the optical signal L from the optical beacon transmitter 3 by the photodiode 22 is output by the preamplifier IC 24. The gain is adjusted and output, and it is sent to the receiver IC 25. The receiver IC 25 is typically composed of a microcomputer or the like, and will be described in detail with reference to a process of reading ID information included in the received signal and a flowchart later. As shown in FIG. Based on the number of cycles received in the data sequence shown), a process for detecting the position of the vehicle 1 in the vehicle width direction is executed. Although not shown in FIG. 5, the preamplifier IC 24 and the receiver IC 25 are also mounted on the substrate 23.
[0029]
Since the optical beacon receiver 4 is generally facing directly upward, it is easily affected by sunlight and ambient light, and therefore a device for reducing these is provided. First, as shown in FIG. 5, a cylindrical light shielding sleeve 26 is attached from the photodiode 22 to the light incident window of the case 21 to block disturbance light entering the photodiode 22 from a lateral direction or an oblique direction. I am doing so. Further, by attaching a light transmission filter 27 that mainly transmits only the optical signal L to the light incident window of the case 21, the influence of sunlight or illumination light is reduced.
[0030]
Next, processing performed by the receiver IC 25 shown in FIG. 6 will be described in detail with reference to FIGS. 7 is a diagram showing various shapes of the reception area A corresponding to each application, FIG. 8 is a main flowchart showing a vehicle position detection process, and FIG. 9 is a timer allocation to the position detection process of FIG. It is a flowchart which shows a loading process.
[0031]
In the first embodiment, a reception area A having the shape shown in FIG. In other words, the reception area A has a substantially trapezoidal shape such that the length in the vehicle traveling direction becomes shorter toward the right, so that the length in the vehicle traveling direction differs depending on the position in the vehicle width direction. Is set to Note that horizontal lines are drawn at regular intervals in the traveling direction of the vehicle in each reception area A shown in FIG. 7, but the interval D between these horizontal lines is determined when the vehicle 1 passes through the reception area A at a certain constant speed. Corresponds to the distance traveled in one cycle of the data sequence (data period).
[0032]
The vehicle width of the vehicle 1 based on the number of times the optical signal L is received by the optical beacon receiver 4 (how many cycles of the data sequence have been received) when the vehicle 1 passes through the reception area A having the shape described above. A process for detecting the direction position is executed. This process will be specifically described below with reference to FIG.
[0033]
First, the header (header portion L1 in FIG. 4A) included in the received signal of the optical beacon receiver 4 is always detected (step a1), and the vehicle 1 enters the reception area A. When the header is detected, the data received following the header (data portion L2 in FIG. 4A) is read (step a2).
[0034]
Then, it is determined whether or not the read data is normal (step a3). If it is normal, it is determined whether or not the same data is continuous (step a4). It recognizes whether it is in progress in the reception area A. Furthermore, a counter function for counting the number of times of reception (how many cycles of the data sequence have been received) is provided. When continuous reception of the same data is confirmed in step a4, the counter is incremented by one ( Step a5). Therefore, for example, in FIG. 7A, every time the vehicle 1 crosses one horizontal line in the reception area A, 1 is added to the counter. If it is determined in step a3 that there is an abnormality in the data, or if continuous reception of the same data is not confirmed in step a4 (that is, if the vehicle 1 leaves the reception area A), the counter Is reset to zero (steps a6 and a7).
[0035]
Here, in addition to the counter function, a timer function is also provided. Following the counter count-up process in step a5, the timer is started (step a8), and the timer interrupt process shown below (FIG. 9). Migrate to Here, the timer time, which is the time from the start to the stop of the timer, is set to a time slightly longer than the data period (time for one cycle in the data sequence). For example, if the data period is 100 msec, the timer time is set to about 110 to 120 msec. The count-up process in step a5 is performed every time the next data is received (that is, in a data cycle), and then the timer is restarted in step a8, so that the vehicle 1 proceeds in the reception area A. While the timer is running, the timer is restarted before the timer expires completely, and thus the timer interrupt process is disabled during that time. On the other hand, when the vehicle 1 exits from the reception area A, the result is No in step a1, so that the timer is not restarted in step a8, and therefore the timer interrupt process is enabled. In this case, the counter stores a final counter value (that is, a counter value immediately before the vehicle 1 leaves the reception area A).
[0036]
Next, the timer interrupt process will be described with reference to FIG.
First, a process of associating the final counter value described above with a position in the vehicle width direction is performed (step b1). For example, as apparent from FIG. 7 (a), the number of horizontal lines crossing differs depending on which position in the vehicle width direction in which the vehicle 1 travels in the reception area A, and this number corresponds to the final counter value. To do. Therefore, if the final counter value is known, it is possible to know which position in the vehicle width direction the vehicle 1 has traveled in the reception area A, that is, the counter value can be associated with the vehicle width direction position on a one-to-one basis. is there.
[0037]
Subsequently, the data (particularly ID information) read in step a2 in FIG. 8 and the vehicle width direction position obtained in step b1 are output to an external controller or the like (step b2). Based on the ID information, it is possible to know the almost accurate traveling position of the vehicle 1 (that is, under which optical beacon transmitter the vehicle 1 is passing), and in addition, the vehicle width direction position of the vehicle 1 can be determined. You can know almost exactly.
[0038]
Thereafter, the counter is reset to zero (step b3). Then, when a predetermined timer time has elapsed, the timer is stopped (step b4), and the timer process ends.
As described above, according to the first embodiment of the present invention, not only the traveling position of the vehicle 1 is detected based on the ID information transmitted from the optical beacon transmitter 3, but also the number of signal receptions. Since the vehicle width direction position of the vehicle 1 can also be known based on (counter value), the position detection accuracy can be greatly improved.
<Second embodiment of the present invention>
Next, a vehicle position detection apparatus according to the second embodiment of the present invention will be described. In the second embodiment, by adopting the reception area A having the shape shown in FIG. 7B, the traveling direction of the vehicle 1 (which direction the traveling path is traveling) can be detected. It is what I did. Since the configuration / arrangement position of the optical beacon and the format of the optical signal L are the same as those in the first embodiment, the description thereof is omitted here.
[0039]
The reception area A shown in FIG. 7B is divided into two regions A1 and A2 in the vehicle traveling direction, and the two regions A1 and A2 have different lengths in the vehicle traveling direction. Is set so that the area A1 is longer than the area A2. The two areas A1 and A2 are both rectangular. In order to form the reception area A having such a shape, for example, as the transparent window 19b of the light shielding plate 19 shown in FIG. 2B, the shape shown in FIG. A substantially similar shape may be employed. In this case, the data received in the two areas A1 and A2 are the same.
[0040]
The number of times of reception of the optical signal L by the optical beacon receiver 4 when the vehicle 1 sequentially passes through the reception area A composed of the two areas A1 and A2 (how many cycles of the data sequence are received) Based on the above, a process for detecting the traveling direction of the vehicle 1 is executed. This process will be specifically described below with reference to FIG.
[0041]
Also in the second embodiment, the same processing as that in the flowchart of FIG. 8 is first executed, and after the counter is finally counted up, the routine proceeds to the timer interrupt processing shown in FIG. In this case, since the reception area A is divided into two areas A1 and A2, each time the vehicle 1 finishes passing through each area, a final counter value is obtained.
[0042]
In this timer interruption process, first, it is determined whether or not the previous data and the current data are the same (step c1). If they are the same, it can be determined that the vehicle 1 has just passed through the two areas A1 and A2 in succession, so the traveling direction of the vehicle 1 is determined from the previous final counter value and the current final counter value. Is determined (step c2). That is, if the vehicle 1 passes through the region A1 after passing through the region A2, the current counter value is larger than the previous counter value, while the vehicle 1 passes through the region A2 after passing through the region A1. In this case, since the current counter value is smaller than the previous counter value, the traveling direction of the vehicle 1 can be determined from the magnitude relationship between the counter values.
[0043]
Subsequently, the data (particularly ID information) read in step a2 of FIG. 8 and the traveling direction obtained in step c2 are output (step c3). Based on the ID information, it is possible to know a substantially accurate traveling position of the vehicle 1, and in addition, it is possible to accurately know the traveling direction of the vehicle 1.
[0044]
Thereafter, the counter is reset to zero (step c4). Then, when the predetermined timer time has elapsed, the timer is stopped (step c5), and the timer process is ended.
In step c1, if it is determined that the previous data is different from the current data, it can be determined that the signal received this time is from an optical beacon transmitter different from the previous one. Therefore, in preparation for the travel direction determination process based on the current and next data and the counter value, the current data is stored as the previous data, and the current counter value is stored as the previous counter value (step c6) The timer process is terminated.
[0045]
As described above, according to the second embodiment of the present invention, not only the traveling position of the vehicle 1 is detected based on the ID information transmitted from the optical beacon transmitter 3, but also the number of signal receptions. Since the traveling direction of the vehicle 1 can also be known based on (counter value), the position detection accuracy can be greatly improved.
<Third embodiment of the present invention>
Next, a vehicle position detection apparatus according to the third embodiment of the present invention will be described. In the third embodiment, the reception area A having the shape shown in FIG. 7C is employed so that both the vehicle width direction position and the traveling direction of the vehicle 1 can be detected. Since the configuration and arrangement position of the optical beacon and the format of the optical signal L are the same as those in the first embodiment, the description thereof is omitted here.
[0046]
The reception area A shown in FIG. 7C is divided into two regions A1 and A2 in the vehicle traveling direction, and the two regions A1 and A2 have different lengths in the vehicle traveling direction. Is set so that the area A1 is longer than the area A2. In addition, the two regions A1 and A2 both have a length in the vehicle traveling direction that is shorter toward the right direction so that the length in the vehicle traveling direction is different in the vehicle width direction position. Such a substantially trapezoidal shape is set. In order to form the receiving area A having such a shape, for example, a transparent window 19b of the light shielding plate 19 shown in FIG. 2 (b) having a shape substantially similar to the shape shown in FIG. 7 (c) is used. Adopt it. In this case, the data received in the two areas A1 and A2 are the same.
[0047]
The number of times of reception of the optical signal L by the optical beacon receiver 4 when the vehicle 1 sequentially passes through the reception area A composed of the two areas A1 and A2 (how many cycles of the data sequence are received) Based on the above, a process of detecting the vehicle width direction position and the traveling direction of the vehicle 1 is executed. This process will be specifically described below with reference to FIG.
[0048]
Also in the second embodiment, the same processing as that in the flowchart of FIG. 8 is first executed, and after the counter is finally counted up, the routine proceeds to the timer interrupt processing shown in FIG. In this case, since the reception area A is divided into two areas A1 and A2, each time the vehicle 1 finishes passing through each area, a final counter value is obtained.
[0049]
In this timer interrupt process, first, it is determined whether or not the previous data and the current data are the same (step d1). If they are the same, it can be determined that the vehicle 1 has just passed through the two areas A1 and A2 in succession, so the traveling direction of the vehicle 1 is determined from the previous final counter value and the current final counter value. Is determined (step d2). This process is the same as the process in step c2 of FIG.
[0050]
Subsequently, a process of associating the previous final counter value and the current final counter value with the vehicle width direction position is performed (step d3). Each of the association processes is the same as the process of step b1 in FIG.
Then, the data (particularly ID information) read in step a2 in FIG. 8, the traveling direction obtained in step d2 and the vehicle width direction position obtained in step d3 are output (step d4). . Based on the ID information, it is possible to know a substantially accurate traveling position of the vehicle 1, and in addition, it is possible to accurately know the traveling direction and the vehicle width direction position of the vehicle 1.
[0051]
Thereafter, the counter is reset to zero (step d5). Then, when a predetermined timer time elapses, the timer is stopped (step d6), and the timer process ends.
If it is determined in step d1 that the previous data is different from the current data, it can be determined that the signal received this time is from an optical beacon transmitter different from the previous one. Therefore, in this case, the current data is stored as the previous data, and the current counter value is stored as the previous counter value (step d7), and the timer process is terminated.
[0052]
As described above, according to the third embodiment of the present invention, not only the traveling position of the vehicle 1 is detected based on the ID information transmitted from the optical beacon transmitter 3, but also the number of signal receptions. Since the traveling direction and the vehicle width direction position of the vehicle 1 can be known based on the (counter value), the position detection accuracy can be further greatly improved.
<Other embodiments>
The present invention is not limited to the above-described embodiment, and various configurations can be adopted within the scope described in each claim. For example, the following configuration changes are possible.
[0053]
(1) In the embodiment described above, the vehicle width direction position and the traveling direction of the vehicle are acquired as the detailed information related to the traveling position of the vehicle. It is also possible to acquire a more accurate position. In that case, for example, a simple rectangular reception area A as shown in FIG. 7 (d) may be used, and signal reception when the vehicle 1 passes through the reception area A as in the above embodiment. If the number of times is counted by a counter, the counter value corresponds to the position in the traveling direction of the vehicle 1 on the reception area A. Therefore, coupled with the sharpness of the edge of the reception area A, it is possible to know a more accurate position in the traveling direction of the vehicle 1 on the reception area A. Specifically, the following methods can be employed.
[0054]
Normally, the ID information included in the optical signal L indicates the coordinates of a specific position in the reception area A. From this, for example, when the ID information indicates the center position P of the reception area A in the vehicle traveling direction, the time when the final counter value is obtained (that is, the vehicle 1 (the optical beacon receiver 4). At the edge of the reception area A in the traveling direction), the distance d corresponding to half of the counter value is added to the coordinates of the central position P to obtain the current traveling direction position of the vehicle 1 ( This corresponds to the position of the edge). Therefore, in this way, it is possible to detect the position in the traveling direction of the vehicle 1 very accurately compared to the case where the position detection is simply performed based on the ID information. Such detection of the position in the traveling direction can be combined with detection of the position in the vehicle width direction and detection of the traveling direction.
[0055]
Further, in the case of the rectangular reception area A as shown in FIG. 7D, since the length in the vehicle traveling direction is the same at any position in the vehicle width direction, the final counter value at a certain vehicle speed is always constant. It is the same, and this can be known in advance. Therefore, for example, when the ID information indicates the center position P in the vehicle traveling direction of the reception area A, the traveling direction position of the vehicle 1 at the time when the counter counts half of the final counter value is obtained. , Corresponding to the position indicated by the ID information (the central position P in the vehicle traveling direction of the reception area A). In this way, it is also possible to accurately detect that the vehicle 1 has reached the center position of the reception area A.
[0056]
In addition, when it is desired to have a desired accuracy in detecting the position in the traveling direction of the vehicle 1, the signal transmission cycle (data cycle) by the optical beacon transmitter 3 is set to the speed of the vehicle 1 and the desired position detection accuracy. Set based on. For example, it is conceivable to set a value (for example, about one half) smaller than a value obtained by dividing the desired position detection accuracy by the vehicle speed as the transmission cycle. As a specific example, the transmission cycle when the vehicle speed is 3 m / sec and the desired position detection accuracy is 0.1 m (= 10 cm) may be set to about 15 msec from the following calculation formula, for example. That is, one cycle may be a data sequence of about 15 msec.
[0057]
{0.1 m / (3 m / sec)} × 1 / 2≈15 msec
Here, the value obtained by dividing the desired position detection accuracy by the vehicle speed is not used as it is as a transmission cycle, but a value smaller than that is generally used for the optical beacon transmitter 3 and the optical beacon receiver 4. Are not completely synchronized, and the position detection process is started only when the header portion of the optical signal L output from the optical beacon transmitter 3 is received by the optical beacon receiver 4 (see FIG. 8). Reference). By performing such setting, a high position detection accuracy of, for example, about 10 to 30 cm can be realized in combination with the sharp edge of the light receiving area A.
[0058]
(2) The shape of each reception area A shown in FIGS. 7A to 7D is merely an example, and the present invention is not limited to this. For example, the reception area A in FIG. 9A is for detecting the position in the vehicle width direction, but if the position detection accuracy may be somewhat rough (for example, stepwise), for example, As shown in FIG. 7E, the edge may be set in a step shape instead of a smooth slope shape.
[0059]
In addition, the reception area A in FIGS. 2B and 2C is divided into two areas A1 and A2, but may be divided into three or more areas.
Furthermore, although the two areas A1 and A2 constituting the reception area A in FIG. 5C are both trapezoidal, for example, either one of the two areas A1 or A2 as shown in FIG. Even if the shape is rectangular, the same effect can be obtained. However, in that case, the length in the vehicle traveling direction in one region is set to be longer than that in the other region at any position in the vehicle width direction.
[0060]
(3) The configuration of the optical beacon transmitter 3 shown in FIG. 2 and the configuration of the optical beacon receiver 4 shown in FIG. 5 are both desirable examples, but the present invention is not limited to this. .
[0061]
【The invention's effect】
According to the present invention, the use of an optical beacon not only enables position detection that sufficiently covers the range of the travel path width of the vehicle by an extremely sharp reception area of the edge, but also increases the number of times the beacon signal is received. Based on this, detailed information related to the traveling position of the vehicle (for example, more accurate position in the traveling direction of the vehicle, position in the vehicle width direction, traveling direction of the vehicle, etc.) can also be acquired. The detection accuracy can be remarkably improved.
[Brief description of the drawings]
1A and 1B are diagrams for explaining a vehicle position detection device according to a first embodiment of the present invention, in which FIG. 1A is a side view of a vehicle travel path in which an optical beacon transmitter is installed, and FIG. It is a top view.
FIG. 2 is a diagram showing a schematic configuration of an optical beacon transmitter 3;
FIG. 3 is a diagram showing a circuit portion of the optical beacon transmitter 3;
4A and 4B are explanatory diagrams of an optical signal L, where FIG. 4A is a diagram illustrating an example of a format of the optical signal L, FIG. 4B is a diagram illustrating a digital data waveform, and FIG. 4C is a diagram illustrating a carrier waveform; .
FIG. 5 is a diagram showing a schematic configuration of an optical beacon receiver 4;
6 is a diagram showing a circuit portion of the optical beacon receiver 4. FIG.
FIG. 7 is a diagram illustrating various shapes of a reception area A according to each application.
FIG. 8 is a main flowchart showing a vehicle position detection process;
FIG. 9 is a flowchart showing a timer interrupt process in the first embodiment of the present invention.
FIG. 10 is a flowchart showing a timer interrupt process in the second embodiment of the present invention.
FIG. 11 is a flowchart showing a timer interrupt process in the third embodiment of the present invention.
[Explanation of symbols]
1 vehicle
2 travel path
3 Optical beacon transmitter
4 optical beacon receiver
11 cases
12 LED
13 Substrate
14 Current limiting resistor
15 Transmitter IC
16 Switching element
18 Horn
19 Shading plate
21 cases
22 Photodiode
23 Substrate
24 Preamplifier IC
25 Transmitter IC
26 sleeve
27 Light transmission filter
L Optical signal
A Reception area

Claims (4)

An optical beacon transmitter that is installed at a key point of a traveling path of a vehicle traveling at a constant speed and repeatedly transmits a signal including its own position information at a constant period, and is transmitted from the optical beacon transmitter mounted on the vehicle. An optical beacon receiver that receives a signal, and a vehicle position detection device that detects a traveling position of the vehicle based on information received by the optical beacon receiver;
Counting means for counting the number of times the signal is received by the optical beacon receiver when the vehicle passes through the reception area of the signal transmitted from the optical beacon transmitter;
Detailed information acquisition means for acquiring detailed information related to the travel position of the vehicle based on the number of receptions counted by the counting means;
The reception area is set so that the length in the vehicle traveling direction differs depending on the position in the vehicle width direction, and the detailed information acquisition means uses the position in the vehicle width direction of the vehicle as the detailed information based on the number of times of reception. car both position detecting device you and obtains. An optical beacon transmitter that is installed at a key point of a vehicle traveling path and repeatedly transmits a signal including its own position information at a fixed period, and a light that is mounted on the vehicle and receives a signal transmitted from the optical beacon transmitter In a vehicle position detection device that has a beacon receiver and detects the traveling position of the vehicle based on information received by the optical beacon receiver,
Counting means for counting the number of times the signal is received by the optical beacon receiver when the vehicle passes through the reception area of the signal transmitted from the optical beacon transmitter;
Detailed information acquisition means for acquiring detailed information related to the travel position of the vehicle based on the number of receptions counted by the counting means;
The reception area is divided into a plurality of regions in the vehicle traveling direction, and the lengths of the plurality of regions in the vehicle traveling direction are set to be different from each other. traveling direction of the detailed information drive both position detecting device you and obtains as. An optical beacon transmitter that is installed at a key point of a traveling path of a vehicle traveling at a constant speed and repeatedly transmits a signal including its own position information at a constant period, and is transmitted from the optical beacon transmitter mounted on the vehicle. An optical beacon receiver that receives a signal, and a vehicle position detection device that detects a traveling position of the vehicle based on information received by the optical beacon receiver;
Counting means for counting the number of times the signal is received by the optical beacon receiver when the vehicle passes through the reception area of the signal transmitted from the optical beacon transmitter;
Detailed information acquisition means for acquiring detailed information related to the travel position of the vehicle based on the number of receptions counted by the counting means;
The reception area is divided into a plurality of regions in the vehicle traveling direction, the lengths of the plurality of regions in the vehicle traveling direction are different from each other, and the length of the vehicle traveling direction in each of the plurality of regions is the vehicle width direction. of being set differently in position, the detailed information obtaining means traveling direction and the vehicle width direction positioning the detailed information drive both position detecting device you and obtains as the vehicle on the basis of the number of receptions . Transmission cycle of the signal by the optical beacon transmitter, the vehicle speed, characterized in that it is set based on the required position detection accuracy claims 1 to 3 vehicle position detecting apparatus according to any one of .

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